Massive Expansion of Shellfish Farming May be Key to Sustainable Aquaculture

When I wrote about a rooftop aquaponic farm in Florida, I noted that aquaculture has a number of advantages over land-based animal husbandry. From the lack of gravity to the lessened need for fish to regulate their body temperatures, water-based farming results in much less entropy, and hence much higher yields per input of food or energy.

But fish tend to eat other fish. And while some of that feed may be made from scraps and waste byproduct, it's not hard to envision a problem with depleting wild fish stocks to feed the farmed ones.

Research also shows that oyster cultivation could be increased substantially in Rhode Island. Former URI graduate student Carrie Byron found that the biomass of cultured oysters could be increased 625 times current levels for Narragansett Bay and 62 times in Rhode Island’s coastal lagoons — or salt ponds — before the ecology of these ecosystems would be affected.

For Narragansett Bay, such an expansion would translate to about 218 million pounds of farmed oysters annually — an amount that is about four times the total estimated annual harvest of fish in the bay. Byron’s “socio-ecological carrying capacity” approach to aquaculture takes into consideration not only these figures and rigorous ecological modeling, but also a stakeholder process.

Scientific findings are showing that shellfish aquaculture, when well managed, can provide solid environmental benefits, such as improving water quality by filtering nutrients and particles from the water and providing habitat for fish and other marine life. Also, as more wild harvesters are diversifying by turning to aquaculture for some part of their livelihoods, traditional animosities between shellfishermen and shellfish growers are receding.